1. Field of the Invention
The present invention relates to a packing pouch which is easy to open.
2. Discussion of the Background
The conventional method of opening a pouch is by cutting it with a knife or scissors or by tearing it at a notch formed in it. The former method is not practicable when a knife or scissors are not at hand; and the latter method does not permit two sheets of film or laminate constituting the pouch to be torn straight and neat in the same direction because of their lack of directional property. Another disadvantage of tear opening is the difficulty in tearing up the strong heat-sealed part.
There have been proposed several ideas to eliminate these disadvantages. For example, Japanese Patent Laid-open No. 123256/1981 discloses a pouch that can be opened straight by the aid of a uniaxially oriented tape bonded to the pouch in the same direction as that in which the pouch is to be torn. Japanese Patent Laid-open No. 26450/1984 and 13661/1985 disclose a pouch provided with a string which is attached to the inside of one of the sheets constituting the pouch, so that one side of the pouch can be opened by pulling the string.
A disadvantage of the pouch mentioned first is an increased production cost due to the additional steps and materials for bonding a uniaxially oriented tape to the pouch. Moreover, the uniaxially oriented tape does not reduce the inherent tear resistance of the pouch. A disadvantage of the pouch mentioned second is the necessity of a special apparatus for accurately attaching a tab to the end of the tearing string. Moreover, pulling the string to tear open the pouch experiences a great resistive force.